A Visit to the Oresund Link with the CEDA Dredging Management Commission and 23 Years Ago with DOT

The CEDA Dredging Management Commission on site visit at the Oresund Link

Edit (11/08/2018): It appears, that my memory fails me on the details. It must have been late 1996 or early 1997.

This week, there was a meeting of the Dredging Management Commission of the CEDA. In this case, the venue was the offices of Femern A/S in Copenhagen1. The objective of the Dredging Management Commission is to provide expertise and guidelines to successfully manage dredging projects. A first publication was the ‘Checklist for Successful Dredging Management’ introduced at the CEDA Dredging Days last November. Currently I am involved in the Working Group on Innovative Dredging Technology2.
One of the items on the agenda was a visit to the artificial island of Peberholm. This island was reclaimed in 1995 during the Oresund Link Project, a tunnel and bridge connection that links Denmark and Sweden over the Oresund. A massive complex project, involving two countries, multiple contractors and numerous suppliers. Unlike most of the complex international government projects, the Oresund Link was delivered ahead of schedule and within budget3.

View from Peberholm on the Oresund Bridge and Sweden

At the time, I did my graduation thesis project with Skanska, one of the main contractors. There were also two other students working with Skanska. And as there were a lot of other Dutch contractors involved, the student club of Dredging and Offshore Technology organised a study tour to the project and have a first-hand experience with this landmark project. Returning to these sites with the CEDA was interesting to see the final product after it’s been working for several year in use.

Students of Dredging and Offshore Technology on study tour in 1995

On the Swedish side, a bridge was a good solution. On the Danish side, the link would be too close, to Copenhagen International Airport to build a bridge. It would interfere with the flight path of approaching planes. Therefore, a sunken section tunnel was chosen. Peberholm was created with fill material, dredged from this tunnel trench. Digging through hard limestone rock, the cutter suction dredge ‘Castor’4 consumed about 62,000 pick points. In the end, they had to exchange all the teeth every 15 minutes, sometimes too hot to handle.

Cutter head of the CSD ‘Castor’

Each pillar and the two pylons of the bridge have a foundation that reaches to the hard bedrock of the Oresund. For this dredging work, amongst others, the back-hoe dredge ‘Rocky’5 from Skanska was deployed. One of the contractual clauses was that turbidity had to be reduced to an absolute minimum, never seen before in any contract. Although protesting, the contractors complied and did a great job on reducing turbidity. The loose material from the bottom and the rubble from the bedrock created visual plumes anyway and Skanska had to modify their procedures and equipment to reach the stringent standards.

Left, Back hoe dredge ‘Rocky’. Middle, bucket of crushed limestone. Right, Spill plume.

It was fitting, that we visited the location of this impressive project as inspiration to advice how to successfully manage a dredging project. The next step to test the management skills of the Danish people will be the Fehmarn Belt Project6.

Panoramic view from Peberholm. Denmark left, Sweden right and Saltholm in the middle.

References

  1. Femern A/S
  2. CEDA Dredging Management Commission, CEDA
  3. Oresund on time and within budget, Øresundsbron
  4. Castor, Van Oord
  5. Rocky (after modification), Boskalis
  6. Fehmarn Belt Project, Wikipedia

See also

¡VAMOS! mining concept for submerged inland mining on any continent

¡VAMOS! equipment on trial at Lee Moor, Devon, UK

Today, the WEDA Dredging Summit and Expo 2018 starts1. Tomorrow, Olivier Marcus is going to present a paper on the ¡VAMOS! project2, I assisted co-authoring. The message we wanted to convey is the applicability of the ¡VAMOS! system we’ve developed in a European Research and Development consortium3. By now we were well acquainted with the European Situation, but as this was going to be presented in the United States I had to do some research all over, for the American market situation. It turned out that ¡VAMOS! concept could be used their as anywhere else.

Schematic of typical vertical ore body in an opencast or submerged setting (Credit: ¡VAMOS!)

First of all, some explanation what the ¡VAMOS! project is about. We’ve noticed that here in Europe mineral resources are heavily depleted or located at locations that are not accessible due to their economic or environmental value. One solution would be to dig deeper, but in open cast mining, you’ll run into an enormous overburden removal and drainage problems. The other is to tunnel mining, but that is very expensive and dangerous. The ¡VAMOS! concept opens up a new approach: submerged mining.

Diagram of the original ¡VAMOS! concept (Credit:¡VAMOS!)

Instead of pumping the water out, we use it to transport the mineral to the plant. And this is very familiar for us in the dredging industry. So, we’ve found another location where we can discover dredging! Usually dredging involves transporting huge volumes of sediment, but the fraction of the ore, that is really paying for the operation tends to be very small. In mining terms it is the ore grade. Depending on the ore grade, the operation can be economically feasible or not. As this is a very fine line, mining economics have already done a lot of research on this and they call it the ‘Exergy Cost’. In short: an operation for low grade ore may be more expensive when the mineral is expensive. In fact, when one is mining sand, the ore grade is 100% and the price will be low, so the profit has to come from its volume.

Exergy cost (kWh) needed for producing a given mineral from bare rock to market. (Credit: Valero)

This model is basically applicable in both the European and the American market. Although the local business mentality will result in different underlying economic calculations. In Europe we were working with a report on the critical resources that are on the agenda of the European Commission4. It turns out, that now the United States has their own list of critical minerals5, just signed into executive order6. The list differs somewhat, but is certainly recognisable. This is a good indication, that the ¡VAMOS! mining concept can be evaluated equally to the other options for the American market.

Medium-Term (2015–2025) Criticality Matrix (Credit: US DOE)

So, who knows, maybe there is an innovative entrepreneur in Olivier’s audience at the WEDA and the first real production model might be put to work in an American mine. At least, when delivering a product like this, we would not have to worry about the Jones Act.

MV handling on LARV at Lee Moor test site in Devon, UK

References

  1. Dredging Summit and Expo 2018, WEDA
  2. WEDA Dredging Summit & Expo, Damen
  3. ¡VAMOS!
  4. EIP on Raw Materials, European Commission
  5. Interior Seeks Public Comment on Draft List of 35 Minerals Deemed Critical to U.S. National Security and the Economy, US Department of the Interior
  6. A Federal Strategy To Ensure Secure and Reliable Supplies of Critical Minerals, Executive Order 13817 of December 20, 2017

See also

Experience the Dredging Experience

Mr. Kommer Damen opening our Damen Dredging Experience

Sorry folks. It has been several weeks since my last post and I hope you haven’t forgotten my dredging details. This website is just a personal side line that I have to maintain and expand in my own time. Lately my time was rather limited and all my creative capabilities were engaged on an urgent case for my employer. But I do have some thoughts that I wanted to share with you, they just have to wait for better times. Part of my job is, to take care of a ‘Dredging Experience Centre’. A touch and feel museum area, where we can take customers and sales- and service people to explain and discuss about their particular dredging project. I have tons of material for presentations and handouts on this topic, so it will be useful next time, when I am otherwise occupied. I just needed an opening to offer you some perspective on the scattered articles that will pop up sometimes.

And what a better opening can be than the opening of the Dredging Experience itself. On Wednesday November 16th, 2016, Mr. Kommer Damen himself opened our new office building and received the honour to show him our exhibits1.

Overview poster for dredging processes and dredging equipment (Colouring page version here)

The starting point of a tour through the dredging experience is the overview poster with all the different processes that are explained with the available exhibits. Each process is indicated at the corresponding dredging vessels, that feature the relevant equipment. Processes and phenomena range from basic soil mechanics to fluid dynamics and the influence of the various processes on the total dredge production. There are also exhibits specifically on explaining our design choices, e.g. our mechanical seal. Other exhibits show recent research and development like ‘spud pole holding forces’ and the DynaCover2.

The Dredging Experience is exactly what it says: you will be able to ‘experience’ the various processes. Most of them require some manual effort and this will show you the differences in soil properties or hydraulic configuration. This provides an excellent opportunity to have an in depth discussion with clients about their particular dredging project and the best possible solution for their specific requirements. Regularly, I see happy faces of enlightenment coming out of the exhibition. Commercial colleagues when they understand the customer across language barriers. And especially customers as they feel at ease, because they can explain on a practical level about their problem and see how much we go into the details of the dredging process to optimize for their purpose. And even when they walk out without buying, they do so with an everlasting positive impression. They will easily apply the new insights into their daily operation at home.

Panorama overview of the ‘Damen Dredging Experience’

The approach in designing and selecting the exhibits was in line with what I learned from my old professor de Koning. He insisted that even as academic students, we still had to examine the dredging processes by hand to truly understand what we were learning3. His favourite quote was from Denis the Rougemont4: ‘But the true condition of man is to think with his hands.’

Professor de Koning (Credit: CEDA)

References

  1. Kommer Damen opening the ‘Damen Dredging Experience’, DredgingToday
  2. DynaCover Outer Pump Casing, Damen
  3. De Koning (1978) ‘Denken met de handen’, TU Delft
  4. De Rougemont (1936) ‘Penser avec les Mains’, Wikipedia

See also